// SPDX-License-Identifier: GPL-2.0 /* * cdc-wdm.c * * This driver supports USB CDC WCM Device Management. * * Copyright (c) 2007-2009 Oliver Neukum * * Some code taken from cdc-acm.c * * Released under the GPLv2. * * Many thanks to Carl Nordbeck */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #define DRIVER_AUTHOR "Oliver Neukum" #define DRIVER_DESC "USB Abstract Control Model driver for USB WCM Device Management" static const struct usb_device_id wdm_ids[] = { { .match_flags = USB_DEVICE_ID_MATCH_INT_CLASS | USB_DEVICE_ID_MATCH_INT_SUBCLASS, .bInterfaceClass = USB_CLASS_COMM, .bInterfaceSubClass = USB_CDC_SUBCLASS_DMM }, { } }; MODULE_DEVICE_TABLE (usb, wdm_ids); #define WDM_MINOR_BASE 176 #define WDM_IN_USE 1 #define WDM_DISCONNECTING 2 #define WDM_RESULT 3 #define WDM_READ 4 #define WDM_INT_STALL 5 #define WDM_POLL_RUNNING 6 #define WDM_RESPONDING 7 #define WDM_SUSPENDING 8 #define WDM_RESETTING 9 #define WDM_OVERFLOW 10 #define WDM_MAX 16 /* CDC-WMC r1.1 requires wMaxCommand to be "at least 256 decimal (0x100)" */ #define WDM_DEFAULT_BUFSIZE 256 static DEFINE_MUTEX(wdm_mutex); static DEFINE_SPINLOCK(wdm_device_list_lock); static LIST_HEAD(wdm_device_list); /* --- method tables --- */ struct wdm_device { u8 *inbuf; /* buffer for response */ u8 *outbuf; /* buffer for command */ u8 *sbuf; /* buffer for status */ u8 *ubuf; /* buffer for copy to user space */ struct urb *command; struct urb *response; struct urb *validity; struct usb_interface *intf; struct usb_ctrlrequest *orq; struct usb_ctrlrequest *irq; spinlock_t iuspin; unsigned long flags; u16 bufsize; u16 wMaxCommand; u16 wMaxPacketSize; __le16 inum; int reslength; int length; int read; int count; dma_addr_t shandle; dma_addr_t ihandle; struct mutex wlock; struct mutex rlock; wait_queue_head_t wait; struct work_struct rxwork; struct work_struct service_outs_intr; int werr; int rerr; int resp_count; struct list_head device_list; int (*manage_power)(struct usb_interface *, int); }; static struct usb_driver wdm_driver; /* return intfdata if we own the interface, else look up intf in the list */ static struct wdm_device *wdm_find_device(struct usb_interface *intf) { struct wdm_device *desc; spin_lock(&wdm_device_list_lock); list_for_each_entry(desc, &wdm_device_list, device_list) if (desc->intf == intf) goto found; desc = NULL; found: spin_unlock(&wdm_device_list_lock); return desc; } static struct wdm_device *wdm_find_device_by_minor(int minor) { struct wdm_device *desc; spin_lock(&wdm_device_list_lock); list_for_each_entry(desc, &wdm_device_list, device_list) if (desc->intf->minor == minor) goto found; desc = NULL; found: spin_unlock(&wdm_device_list_lock); return desc; } /* --- callbacks --- */ static void wdm_out_callback(struct urb *urb) { struct wdm_device *desc; unsigned long flags; desc = urb->context; spin_lock_irqsave(&desc->iuspin, flags); desc->werr = urb->status; spin_unlock_irqrestore(&desc->iuspin, flags); kfree(desc->outbuf); desc->outbuf = NULL; clear_bit(WDM_IN_USE, &desc->flags); wake_up(&desc->wait); } static void wdm_in_callback(struct urb *urb) { unsigned long flags; struct wdm_device *desc = urb->context; int status = urb->status; int length = urb->actual_length; spin_lock_irqsave(&desc->iuspin, flags); clear_bit(WDM_RESPONDING, &desc->flags); if (status) { switch (status) { case -ENOENT: dev_dbg(&desc->intf->dev, "nonzero urb status received: -ENOENT\n"); goto skip_error; case -ECONNRESET: dev_dbg(&desc->intf->dev, "nonzero urb status received: -ECONNRESET\n"); goto skip_error; case -ESHUTDOWN: dev_dbg(&desc->intf->dev, "nonzero urb status received: -ESHUTDOWN\n"); goto skip_error; case -EPIPE: dev_err(&desc->intf->dev, "nonzero urb status received: -EPIPE\n"); break; default: dev_err(&desc->intf->dev, "Unexpected error %d\n", status); break; } } /* * only set a new error if there is no previous error. * Errors are only cleared during read/open * Avoid propagating -EPIPE (stall) to userspace since it is * better handled as an empty read */ if (desc->rerr == 0 && status != -EPIPE) desc->rerr = status; if (length + desc->length > desc->wMaxCommand) { /* The buffer would overflow */ set_bit(WDM_OVERFLOW, &desc->flags); } else { /* we may already be in overflow */ if (!test_bit(WDM_OVERFLOW, &desc->flags)) { memmove(desc->ubuf + desc->length, desc->inbuf, length); desc->length += length; desc->reslength = length; } } skip_error: if (desc->rerr) { /* * Since there was an error, userspace may decide to not read * any data after poll'ing. * We should respond to further attempts from the device to send * data, so that we can get unstuck. */ schedule_work(&desc->service_outs_intr); } else { set_bit(WDM_READ, &desc->flags); wake_up(&desc->wait); } spin_unlock_irqrestore(&desc->iuspin, flags); } static void wdm_int_callback(struct urb *urb) { unsigned long flags; int rv = 0; int responding; int status = urb->status; struct wdm_device *desc; struct usb_cdc_notification *dr; desc = urb->context; dr = (struct usb_cdc_notification *)desc->sbuf; if (status) { switch (status) { case -ESHUTDOWN: case -ENOENT: case -ECONNRESET: return; /* unplug */ case -EPIPE: set_bit(WDM_INT_STALL, &desc->flags); dev_err(&desc->intf->dev, "Stall on int endpoint\n"); goto sw; /* halt is cleared in work */ default: dev_err(&desc->intf->dev, "nonzero urb status received: %d\n", status); break; } } if (urb->actual_length < sizeof(struct usb_cdc_notification)) { dev_err(&desc->intf->dev, "wdm_int_callback - %d bytes\n", urb->actual_length); goto exit; } switch (dr->bNotificationType) { case USB_CDC_NOTIFY_RESPONSE_AVAILABLE: dev_dbg(&desc->intf->dev, "NOTIFY_RESPONSE_AVAILABLE received: index %d len %d\n", le16_to_cpu(dr->wIndex), le16_to_cpu(dr->wLength)); break; case USB_CDC_NOTIFY_NETWORK_CONNECTION: dev_dbg(&desc->intf->dev, "NOTIFY_NETWORK_CONNECTION %s network\n", dr->wValue ? "connected to" : "disconnected from"); goto exit; case USB_CDC_NOTIFY_SPEED_CHANGE: dev_dbg(&desc->intf->dev, "SPEED_CHANGE received (len %u)\n", urb->actual_length); goto exit; default: clear_bit(WDM_POLL_RUNNING, &desc->flags); dev_err(&desc->intf->dev, "unknown notification %d received: index %d len %d\n", dr->bNotificationType, le16_to_cpu(dr->wIndex), le16_to_cpu(dr->wLength)); goto exit; } spin_lock_irqsave(&desc->iuspin, flags); responding = test_and_set_bit(WDM_RESPONDING, &desc->flags); if (!desc->resp_count++ && !responding && !test_bit(WDM_DISCONNECTING, &desc->flags) && !test_bit(WDM_SUSPENDING, &desc->flags)) { rv = usb_submit_urb(desc->response, GFP_ATOMIC); dev_dbg(&desc->intf->dev, "submit response URB %d\n", rv); } spin_unlock_irqrestore(&desc->iuspin, flags); if (rv < 0) { clear_bit(WDM_RESPONDING, &desc->flags); if (rv == -EPERM) return; if (rv == -ENOMEM) { sw: rv = schedule_work(&desc->rxwork); if (rv) dev_err(&desc->intf->dev, "Cannot schedule work\n"); } } exit: rv = usb_submit_urb(urb, GFP_ATOMIC); if (rv) dev_err(&desc->intf->dev, "%s - usb_submit_urb failed with result %d\n", __func__, rv); } static void kill_urbs(struct wdm_device *desc) { /* the order here is essential */ usb_kill_urb(desc->command); usb_kill_urb(desc->validity); usb_kill_urb(desc->response); } static void free_urbs(struct wdm_device *desc) { usb_free_urb(desc->validity); usb_free_urb(desc->response); usb_free_urb(desc->command); } static void cleanup(struct wdm_device *desc) { kfree(desc->sbuf); kfree(desc->inbuf); kfree(desc->orq); kfree(desc->irq); kfree(desc->ubuf); free_urbs(desc); kfree(desc); } static ssize_t wdm_write (struct file *file, const char __user *buffer, size_t count, loff_t *ppos) { u8 *buf; int rv = -EMSGSIZE, r, we; struct wdm_device *desc = file->private_data; struct usb_ctrlrequest *req; if (count > desc->wMaxCommand) count = desc->wMaxCommand; spin_lock_irq(&desc->iuspin); we = desc->werr; desc->werr = 0; spin_unlock_irq(&desc->iuspin); if (we < 0) return usb_translate_errors(we); buf = memdup_user(buffer, count); if (IS_ERR(buf)) return PTR_ERR(buf); /* concurrent writes and disconnect */ r = mutex_lock_interruptible(&desc->wlock); rv = -ERESTARTSYS; if (r) goto out_free_mem; if (test_bit(WDM_DISCONNECTING, &desc->flags)) { rv = -ENODEV; goto out_free_mem_lock; } r = usb_autopm_get_interface(desc->intf); if (r < 0) { rv = usb_translate_errors(r); goto out_free_mem_lock; } if (!(file->f_flags & O_NONBLOCK)) r = wait_event_interruptible(desc->wait, !test_bit(WDM_IN_USE, &desc->flags)); else if (test_bit(WDM_IN_USE, &desc->flags)) r = -EAGAIN; if (test_bit(WDM_RESETTING, &desc->flags)) r = -EIO; if (r < 0) { rv = r; goto out_free_mem_pm; } req = desc->orq; usb_fill_control_urb( desc->command, interface_to_usbdev(desc->intf), /* using common endpoint 0 */ usb_sndctrlpipe(interface_to_usbdev(desc->intf), 0), (unsigned char *)req, buf, count, wdm_out_callback, desc ); req->bRequestType = (USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_INTERFACE); req->bRequest = USB_CDC_SEND_ENCAPSULATED_COMMAND; req->wValue = 0; req->wIndex = desc->inum; /* already converted */ req->wLength = cpu_to_le16(count); set_bit(WDM_IN_USE, &desc->flags); desc->outbuf = buf; rv = usb_submit_urb(desc->command, GFP_KERNEL); if (rv < 0) { desc->outbuf = NULL; clear_bit(WDM_IN_USE, &desc->flags); dev_err(&desc->intf->dev, "Tx URB error: %d\n", rv); rv = usb_translate_errors(rv); goto out_free_mem_pm; } else { dev_dbg(&desc->intf->dev, "Tx URB has been submitted index=%d\n", le16_to_cpu(req->wIndex)); } usb_autopm_put_interface(desc->intf); mutex_unlock(&desc->wlock); return count; out_free_mem_pm: usb_autopm_put_interface(desc->intf); out_free_mem_lock: mutex_unlock(&desc->wlock); out_free_mem: kfree(buf); return rv; } /* * Submit the read urb if resp_count is non-zero. * * Called with desc->iuspin locked */ static int service_outstanding_interrupt(struct wdm_device *desc) { int rv = 0; /* submit read urb only if the device is waiting for it */ if (!desc->resp_count || !--desc->resp_count) goto out; set_bit(WDM_RESPONDING, &desc->flags); spin_unlock_irq(&desc->iuspin); rv = usb_submit_urb(desc->response, GFP_KERNEL); spin_lock_irq(&desc->iuspin); if (rv) { dev_err(&desc->intf->dev, "usb_submit_urb failed with result %d\n", rv); /* make sure the next notification trigger a submit */ clear_bit(WDM_RESPONDING, &desc->flags); desc->resp_count = 0; } out: return rv; } static ssize_t wdm_read (struct file *file, char __user *buffer, size_t count, loff_t *ppos) { int rv, cntr; int i = 0; struct wdm_device *desc = file->private_data; rv = mutex_lock_interruptible(&desc->rlock); /*concurrent reads */ if (rv < 0) return -ERESTARTSYS; cntr = READ_ONCE(desc->length); if (cntr == 0) { desc->read = 0; retry: if (test_bit(WDM_DISCONNECTING, &desc->flags)) { rv = -ENODEV; goto err; } if (test_bit(WDM_OVERFLOW, &desc->flags)) { clear_bit(WDM_OVERFLOW, &desc->flags); rv = -ENOBUFS; goto err; } i++; if (file->f_flags & O_NONBLOCK) { if (!test_bit(WDM_READ, &desc->flags)) { rv = -EAGAIN; goto err; } rv = 0; } else { rv = wait_event_interruptible(desc->wait, test_bit(WDM_READ, &desc->flags)); } /* may have happened while we slept */ if (test_bit(WDM_DISCONNECTING, &desc->flags)) { rv = -ENODEV; goto err; } if (test_bit(WDM_RESETTING, &desc->flags)) { rv = -EIO; goto err; } usb_mark_last_busy(interface_to_usbdev(desc->intf)); if (rv < 0) { rv = -ERESTARTSYS; goto err; } spin_lock_irq(&desc->iuspin); if (desc->rerr) { /* read completed, error happened */ rv = usb_translate_errors(desc->rerr); desc->rerr = 0; spin_unlock_irq(&desc->iuspin); goto err; } /* * recheck whether we've lost the race * against the completion handler */ if (!test_bit(WDM_READ, &desc->flags)) { /* lost race */ spin_unlock_irq(&desc->iuspin); goto retry; } if (!desc->reslength) { /* zero length read */ dev_dbg(&desc->intf->dev, "zero length - clearing WDM_READ\n"); clear_bit(WDM_READ, &desc->flags); rv = service_outstanding_interrupt(desc); spin_unlock_irq(&desc->iuspin); if (rv < 0) goto err; goto retry; } cntr = desc->length; spin_unlock_irq(&desc->iuspin); } if (cntr > count) cntr = count; rv = copy_to_user(buffer, desc->ubuf, cntr); if (rv > 0) { rv = -EFAULT; goto err; } spin_lock_irq(&desc->iuspin); for (i = 0; i < desc->length - cntr; i++) desc->ubuf[i] = desc->ubuf[i + cntr]; desc->length -= cntr; /* in case we had outstanding data */ if (!desc->length) { clear_bit(WDM_READ, &desc->flags); service_outstanding_interrupt(desc); } spin_unlock_irq(&desc->iuspin); rv = cntr; err: mutex_unlock(&desc->rlock); return rv; } static int wdm_flush(struct file *file, fl_owner_t id) { struct wdm_device *desc = file->private_data; wait_event(desc->wait, /* * needs both flags. We cannot do with one * because resetting it would cause a race * with write() yet we need to signal * a disconnect */ !test_bit(WDM_IN_USE, &desc->flags) || test_bit(WDM_DISCONNECTING, &desc->flags)); /* cannot dereference desc->intf if WDM_DISCONNECTING */ if (test_bit(WDM_DISCONNECTING, &desc->flags)) return -ENODEV; if (desc->werr < 0) dev_err(&desc->intf->dev, "Error in flush path: %d\n", desc->werr); return usb_translate_errors(desc->werr); } static __poll_t wdm_poll(struct file *file, struct poll_table_struct *wait) { struct wdm_device *desc = file->private_data; unsigned long flags; __poll_t mask = 0; spin_lock_irqsave(&desc->iuspin, flags); if (test_bit(WDM_DISCONNECTING, &desc->flags)) { mask = EPOLLHUP | EPOLLERR; spin_unlock_irqrestore(&desc->iuspin, flags); goto desc_out; } if (test_bit(WDM_READ, &desc->flags)) mask = EPOLLIN | EPOLLRDNORM; if (desc->rerr || desc->werr) mask |= EPOLLERR; if (!test_bit(WDM_IN_USE, &desc->flags)) mask |= EPOLLOUT | EPOLLWRNORM; spin_unlock_irqrestore(&desc->iuspin, flags); poll_wait(file, &desc->wait, wait); desc_out: return mask; } static int wdm_open(struct inode *inode, struct file *file) { int minor = iminor(inode); int rv = -ENODEV; struct usb_interface *intf; struct wdm_device *desc; mutex_lock(&wdm_mutex); desc = wdm_find_device_by_minor(minor); if (!desc) goto out; intf = desc->intf; if (test_bit(WDM_DISCONNECTING, &desc->flags)) goto out; file->private_data = desc; rv = usb_autopm_get_interface(desc->intf); if (rv < 0) { dev_err(&desc->intf->dev, "Error autopm - %d\n", rv); goto out; } /* using write lock to protect desc->count */ mutex_lock(&desc->wlock); if (!desc->count++) { desc->werr = 0; desc->rerr = 0; rv = usb_submit_urb(desc->validity, GFP_KERNEL); if (rv < 0) { desc->count--; dev_err(&desc->intf->dev, "Error submitting int urb - %d\n", rv); rv = usb_translate_errors(rv); } } else { rv = 0; } mutex_unlock(&desc->wlock); if (desc->count == 1) desc->manage_power(intf, 1); usb_autopm_put_interface(desc->intf); out: mutex_unlock(&wdm_mutex); return rv; } static int wdm_release(struct inode *inode, struct file *file) { struct wdm_device *desc = file->private_data; mutex_lock(&wdm_mutex); /* using write lock to protect desc->count */ mutex_lock(&desc->wlock); desc->count--; mutex_unlock(&desc->wlock); if (!desc->count) { if (!test_bit(WDM_DISCONNECTING, &desc->flags)) { dev_dbg(&desc->intf->dev, "wdm_release: cleanup\n"); kill_urbs(desc); spin_lock_irq(&desc->iuspin); desc->resp_count = 0; spin_unlock_irq(&desc->iuspin); desc->manage_power(desc->intf, 0); } else { /* must avoid dev_printk here as desc->intf is invalid */ pr_debug(KBUILD_MODNAME " %s: device gone - cleaning up\n", __func__); cleanup(desc); } } mutex_unlock(&wdm_mutex); return 0; } static long wdm_ioctl(struct file *file, unsigned int cmd, unsigned long arg) { struct wdm_device *desc = file->private_data; int rv = 0; switch (cmd) { case IOCTL_WDM_MAX_COMMAND: if (copy_to_user((void __user *)arg, &desc->wMaxCommand, sizeof(desc->wMaxCommand))) rv = -EFAULT; break; default: rv = -ENOTTY; } return rv; } static const struct file_operations wdm_fops = { .owner = THIS_MODULE, .read = wdm_read, .write = wdm_write, .open = wdm_open, .flush = wdm_flush, .release = wdm_release, .poll = wdm_poll, .unlocked_ioctl = wdm_ioctl, .compat_ioctl = wdm_ioctl, .llseek = noop_llseek, }; static struct usb_class_driver wdm_class = { .name = "cdc-wdm%d", .fops = &wdm_fops, .minor_base = WDM_MINOR_BASE, }; /* --- error handling --- */ static void wdm_rxwork(struct work_struct *work) { struct wdm_device *desc = container_of(work, struct wdm_device, rxwork); unsigned long flags; int rv = 0; int responding; spin_lock_irqsave(&desc->iuspin, flags); if (test_bit(WDM_DISCONNECTING, &desc->flags)) { spin_unlock_irqrestore(&desc->iuspin, flags); } else { responding = test_and_set_bit(WDM_RESPONDING, &desc->flags); spin_unlock_irqrestore(&desc->iuspin, flags); if (!responding) rv = usb_submit_urb(desc->response, GFP_KERNEL); if (rv < 0 && rv != -EPERM) { spin_lock_irqsave(&desc->iuspin, flags); clear_bit(WDM_RESPONDING, &desc->flags); if (!test_bit(WDM_DISCONNECTING, &desc->flags)) schedule_work(&desc->rxwork); spin_unlock_irqrestore(&desc->iuspin, flags); } } } static void service_interrupt_work(struct work_struct *work) { struct wdm_device *desc; desc = container_of(work, struct wdm_device, service_outs_intr); spin_lock_irq(&desc->iuspin); service_outstanding_interrupt(desc); if (!desc->resp_count) { set_bit(WDM_READ, &desc->flags); wake_up(&desc->wait); } spin_unlock_irq(&desc->iuspin); } /* --- hotplug --- */ static int wdm_create(struct usb_interface *intf, struct usb_endpoint_descriptor *ep, u16 bufsize, int (*manage_power)(struct usb_interface *, int)) { int rv = -ENOMEM; struct wdm_device *desc; desc = kzalloc(sizeof(struct wdm_device), GFP_KERNEL); if (!desc) goto out; INIT_LIST_HEAD(&desc->device_list); mutex_init(&desc->rlock); mutex_init(&desc->wlock); spin_lock_init(&desc->iuspin); init_waitqueue_head(&desc->wait); desc->wMaxCommand = bufsize; /* this will be expanded and needed in hardware endianness */ desc->inum = cpu_to_le16((u16)intf->cur_altsetting->desc.bInterfaceNumber); desc->intf = intf; INIT_WORK(&desc->rxwork, wdm_rxwork); INIT_WORK(&desc->service_outs_intr, service_interrupt_work); rv = -EINVAL; if (!usb_endpoint_is_int_in(ep)) goto err; desc->wMaxPacketSize = usb_endpoint_maxp(ep); desc->orq = kmalloc(sizeof(struct usb_ctrlrequest), GFP_KERNEL); if (!desc->orq) goto err; desc->irq = kmalloc(sizeof(struct usb_ctrlrequest), GFP_KERNEL); if (!desc->irq) goto err; desc->validity = usb_alloc_urb(0, GFP_KERNEL); if (!desc->validity) goto err; desc->response = usb_alloc_urb(0, GFP_KERNEL); if (!desc->response) goto err; desc->command = usb_alloc_urb(0, GFP_KERNEL); if (!desc->command) goto err; desc->ubuf = kmalloc(desc->wMaxCommand, GFP_KERNEL); if (!desc->ubuf) goto err; desc->sbuf = kmalloc(desc->wMaxPacketSize, GFP_KERNEL); if (!desc->sbuf) goto err; desc->inbuf = kmalloc(desc->wMaxCommand, GFP_KERNEL); if (!desc->inbuf) goto err; usb_fill_int_urb( desc->validity, interface_to_usbdev(intf), usb_rcvintpipe(interface_to_usbdev(intf), ep->bEndpointAddress), desc->sbuf, desc->wMaxPacketSize, wdm_int_callback, desc, ep->bInterval ); desc->irq->bRequestType = (USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE); desc->irq->bRequest = USB_CDC_GET_ENCAPSULATED_RESPONSE; desc->irq->wValue = 0; desc->irq->wIndex = desc->inum; /* already converted */ desc->irq->wLength = cpu_to_le16(desc->wMaxCommand); usb_fill_control_urb( desc->response, interface_to_usbdev(intf), /* using common endpoint 0 */ usb_rcvctrlpipe(interface_to_usbdev(desc->intf), 0), (unsigned char *)desc->irq, desc->inbuf, desc->wMaxCommand, wdm_in_callback, desc ); desc->manage_power = manage_power; spin_lock(&wdm_device_list_lock); list_add(&desc->device_list, &wdm_device_list); spin_unlock(&wdm_device_list_lock); rv = usb_register_dev(intf, &wdm_class); if (rv < 0) goto err; else dev_info(&intf->dev, "%s: USB WDM device\n", dev_name(intf->usb_dev)); out: return rv; err: spin_lock(&wdm_device_list_lock); list_del(&desc->device_list); spin_unlock(&wdm_device_list_lock); cleanup(desc); return rv; } static int wdm_manage_power(struct usb_interface *intf, int on) { /* need autopm_get/put here to ensure the usbcore sees the new value */ int rv = usb_autopm_get_interface(intf); intf->needs_remote_wakeup = on; if (!rv) usb_autopm_put_interface(intf); return 0; } static int wdm_probe(struct usb_interface *intf, const struct usb_device_id *id) { int rv = -EINVAL; struct usb_host_interface *iface; struct usb_endpoint_descriptor *ep; struct usb_cdc_parsed_header hdr; u8 *buffer = intf->altsetting->extra; int buflen = intf->altsetting->extralen; u16 maxcom = WDM_DEFAULT_BUFSIZE; if (!buffer) goto err; cdc_parse_cdc_header(&hdr, intf, buffer, buflen); if (hdr.usb_cdc_dmm_desc) maxcom = le16_to_cpu(hdr.usb_cdc_dmm_desc->wMaxCommand); iface = intf->cur_altsetting; if (iface->desc.bNumEndpoints != 1) goto err; ep = &iface->endpoint[0].desc; rv = wdm_create(intf, ep, maxcom, &wdm_manage_power); err: return rv; } /** * usb_cdc_wdm_register - register a WDM subdriver * @intf: usb interface the subdriver will associate with * @ep: interrupt endpoint to monitor for notifications * @bufsize: maximum message size to support for read/write * * Create WDM usb class character device and associate it with intf * without binding, allowing another driver to manage the interface. * * The subdriver will manage the given interrupt endpoint exclusively * and will issue control requests referring to the given intf. It * will otherwise avoid interferring, and in particular not do * usb_set_intfdata/usb_get_intfdata on intf. * * The return value is a pointer to the subdriver's struct usb_driver. * The registering driver is responsible for calling this subdriver's * disconnect, suspend, resume, pre_reset and post_reset methods from * its own. */ struct usb_driver *usb_cdc_wdm_register(struct usb_interface *intf, struct usb_endpoint_descriptor *ep, int bufsize, int (*manage_power)(struct usb_interface *, int)) { int rv = -EINVAL; rv = wdm_create(intf, ep, bufsize, manage_power); if (rv < 0) goto err; return &wdm_driver; err: return ERR_PTR(rv); } EXPORT_SYMBOL(usb_cdc_wdm_register); static void wdm_disconnect(struct usb_interface *intf) { struct wdm_device *desc; unsigned long flags; usb_deregister_dev(intf, &wdm_class); desc = wdm_find_device(intf); mutex_lock(&wdm_mutex); /* the spinlock makes sure no new urbs are generated in the callbacks */ spin_lock_irqsave(&desc->iuspin, flags); set_bit(WDM_DISCONNECTING, &desc->flags); set_bit(WDM_READ, &desc->flags); spin_unlock_irqrestore(&desc->iuspin, flags); wake_up_all(&desc->wait); mutex_lock(&desc->rlock); mutex_lock(&desc->wlock); kill_urbs(desc); cancel_work_sync(&desc->rxwork); cancel_work_sync(&desc->service_outs_intr); mutex_unlock(&desc->wlock); mutex_unlock(&desc->rlock); /* the desc->intf pointer used as list key is now invalid */ spin_lock(&wdm_device_list_lock); list_del(&desc->device_list); spin_unlock(&wdm_device_list_lock); if (!desc->count) cleanup(desc); else dev_dbg(&intf->dev, "%d open files - postponing cleanup\n", desc->count); mutex_unlock(&wdm_mutex); } #ifdef CONFIG_PM static int wdm_suspend(struct usb_interface *intf, pm_message_t message) { struct wdm_device *desc = wdm_find_device(intf); int rv = 0; dev_dbg(&desc->intf->dev, "wdm%d_suspend\n", intf->minor); /* if this is an autosuspend the caller does the locking */ if (!PMSG_IS_AUTO(message)) { mutex_lock(&desc->rlock); mutex_lock(&desc->wlock); } spin_lock_irq(&desc->iuspin); if (PMSG_IS_AUTO(message) && (test_bit(WDM_IN_USE, &desc->flags) || test_bit(WDM_RESPONDING, &desc->flags))) { spin_unlock_irq(&desc->iuspin); rv = -EBUSY; } else { set_bit(WDM_SUSPENDING, &desc->flags); spin_unlock_irq(&desc->iuspin); /* callback submits work - order is essential */ kill_urbs(desc); cancel_work_sync(&desc->rxwork); cancel_work_sync(&desc->service_outs_intr); } if (!PMSG_IS_AUTO(message)) { mutex_unlock(&desc->wlock); mutex_unlock(&desc->rlock); } return rv; } #endif static int recover_from_urb_loss(struct wdm_device *desc) { int rv = 0; if (desc->count) { rv = usb_submit_urb(desc->validity, GFP_NOIO); if (rv < 0) dev_err(&desc->intf->dev, "Error resume submitting int urb - %d\n", rv); } return rv; } #ifdef CONFIG_PM static int wdm_resume(struct usb_interface *intf) { struct wdm_device *desc = wdm_find_device(intf); int rv; dev_dbg(&desc->intf->dev, "wdm%d_resume\n", intf->minor); clear_bit(WDM_SUSPENDING, &desc->flags); rv = recover_from_urb_loss(desc); return rv; } #endif static int wdm_pre_reset(struct usb_interface *intf) { struct wdm_device *desc = wdm_find_device(intf); /* * we notify everybody using poll of * an exceptional situation * must be done before recovery lest a spontaneous * message from the device is lost */ spin_lock_irq(&desc->iuspin); set_bit(WDM_RESETTING, &desc->flags); /* inform read/write */ set_bit(WDM_READ, &desc->flags); /* unblock read */ clear_bit(WDM_IN_USE, &desc->flags); /* unblock write */ desc->rerr = -EINTR; spin_unlock_irq(&desc->iuspin); wake_up_all(&desc->wait); mutex_lock(&desc->rlock); mutex_lock(&desc->wlock); kill_urbs(desc); cancel_work_sync(&desc->rxwork); cancel_work_sync(&desc->service_outs_intr); return 0; } static int wdm_post_reset(struct usb_interface *intf) { struct wdm_device *desc = wdm_find_device(intf); int rv; clear_bit(WDM_OVERFLOW, &desc->flags); clear_bit(WDM_RESETTING, &desc->flags); rv = recover_from_urb_loss(desc); mutex_unlock(&desc->wlock); mutex_unlock(&desc->rlock); return 0; } static struct usb_driver wdm_driver = { .name = "cdc_wdm", .probe = wdm_probe, .disconnect = wdm_disconnect, #ifdef CONFIG_PM .suspend = wdm_suspend, .resume = wdm_resume, .reset_resume = wdm_resume, #endif .pre_reset = wdm_pre_reset, .post_reset = wdm_post_reset, .id_table = wdm_ids, .supports_autosuspend = 1, .disable_hub_initiated_lpm = 1, }; module_usb_driver(wdm_driver); MODULE_AUTHOR(DRIVER_AUTHOR); MODULE_DESCRIPTION(DRIVER_DESC); MODULE_LICENSE("GPL");